OK.
On Tue, Mar 13, 2018 at 4:17 PM, Jakub Jelinek <ja...@redhat.com> wrote: > Hi! > > If we return olddecl on an (invalid) builtin function redefinition rather > than redeclaration, we ICE shortly afterwards, because we assume we have > non-NULL DECL_INITIAL on whatever is returned (except for error_mark_node). > > The following patch errors unconditionally for definitions of builtin > functions, and also makes sure to return error_mark_node if we've emitted > an error from the permerror. > > Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk? > > 2018-03-13 Jakub Jelinek <ja...@redhat.com> > > PR c++/84843 > * decl.c (duplicate_decls): For redefinition of built-in, use error > and return error_mark_node. For redeclaration, return error_mark_node > rather than olddecl if !flag_permissive. > > * g++.dg/ext/pr84843-1.C: New test. > * g++.dg/ext/pr84843-2.C: New test. > > --- gcc/cp/decl.c.jj 2018-03-09 19:00:44.350969146 +0100 > +++ gcc/cp/decl.c 2018-03-13 14:56:45.244872506 +0100 > @@ -1583,13 +1583,20 @@ next_arg:; > || memcmp (name + len - strlen ("_chk"), > "_chk", strlen ("_chk") + 1) != 0)) > { > + if (DECL_INITIAL (newdecl)) > + { > + error_at (DECL_SOURCE_LOCATION (newdecl), > + "definition of %q#D ambiguates built-in " > + "declaration %q#D", newdecl, olddecl); > + return error_mark_node; > + } > if (permerror (DECL_SOURCE_LOCATION (newdecl), > "new declaration %q#D ambiguates > built-in" > " declaration %q#D", newdecl, olddecl) > && flag_permissive) > inform (DECL_SOURCE_LOCATION (newdecl), > "ignoring the %q#D declaration", newdecl); > - return olddecl; > + return flag_permissive ? olddecl : error_mark_node; > } > } > > --- gcc/testsuite/g++.dg/ext/pr84843-1.C.jj 2018-03-13 14:55:15.927831678 > +0100 > +++ gcc/testsuite/g++.dg/ext/pr84843-1.C 2018-03-13 14:57:51.652902862 > +0100 > @@ -0,0 +1,9 @@ > +// PR c++/84843 > +// { dg-do compile } > +// { dg-options "-fpermissive" } > + > +extern "C" int > +__atomic_compare_exchange (int x, int y) // { dg-error "ambiguates > built-in declaration" } > +{ > + return x + y; > +} > --- gcc/testsuite/g++.dg/ext/pr84843-2.C.jj 2018-03-13 14:55:19.349833246 > +0100 > +++ gcc/testsuite/g++.dg/ext/pr84843-2.C 2018-03-13 14:57:58.205905859 > +0100 > @@ -0,0 +1,9 @@ > +// PR c++/84843 > +// { dg-do compile } > +// { dg-options "" } > + > +extern "C" int > +__atomic_compare_exchange (int x, int y) // { dg-error "ambiguates > built-in declaration" } > +{ > + return x + y; > +} > > Jakub